Bent axis pumps usually comprise a front body having a revolving shaft operatively connected to pistons for the pump suction and delivery, and a back fixed body that comprises the pump suction and delivery channels.
A central revolving body or cylinder body, integral in rotation with the shaft, is inserted between the front body and the back body. The central body comprises the cylinders suitable for seating the pistons.
The central body is inclined relative to the front body, so that the sliding axis of the pistons is bent relative to the axis of rotation of the front body.
The shaft of the front body is integral with the pistons so as to transmit the rotation motion thereto.
The inclination between the axis of rotation of the front body determines the alternating motion of the pistons relative to the cylinders following the rotation of pistons relative to the axis of rotation of the front body.
The central body is associated to the back fixed body by a pin integral with the back body.
Thus, a fixing portion of the pin is integrally constrained to the back body whereas a guiding portion of the pin couples with a relative seat of the central body. Such guiding portion has the function of being a guide for the rotation of the central body and is subject to a friction action by the pin itself.
The coupling between pin and central body is a critical point of the pump.
In fact, even slight shifts between the pin and the central body generate such stresses as to quickly cause the breakage of the pin.
To obviate such disadvantage, in the art it is known to strengthen the pin also through the application of coating materials and increase the lubrication between the pin and the central body seat. Nevertheless, breakage phenomena are not prevented and the pin life is quite limited.